Experimental manipulation of a unique cue in Pavlovian SCR conditioning with humans

We report two experiments on positive and negative patterning in human skin conductance response (SCR) conditioning with a manipulable unique cue. In experiment 1 flashing red lights? arrayed horizontally, were used as elemen ts and apparent movement was used as additional (unique) cue when the eleme nts were presented in compound. Positive and negative patternings were both acquired readily, and positive patterning transferred to new stimuli (gree n lights, vertically arrayed). The unique cue did not influence these outco mes. Experiment 2 examined only positive patterning, using a more conventio nal unique cue, a visual frame that surrounded the letter stimuli on compou nd trials but not on element trials. The unique cue again facilitated neith er acquisition nor transfer. These results do not support either the unique cue extension of the Rescorla-Wagner theory or configural theories. Human participants seem to utilize 'size' or 'number' or some other abstract feat ure in preference to available concrete stimuli. (C) 2000 Elsevier Science B.V. All rights reserved.